Mercurial > sdl-ios-xcode
view docs/man3/SDL_JoystickGetBall.3 @ 4352:c8bf421431f9 SDL-1.2
Fixed bug #853
Ludwig Nussel 2009-10-18 05:34:18 PDT
src/joystick/linux/SDL_sysjoystick.c has some problems:
- test_bit() might break with strict aliasing
- test_bit() assumes array is Uint32 but its actually "unsigned long"
on 64bit systems sizeof(long) != sizeof(Uint32).
- the keybit array is too small
- the arrays are unitialized so the number of
detected buttons is quite random
| author | Sam Lantinga <slouken@libsdl.org> |
|---|---|
| date | Sun, 18 Oct 2009 16:14:57 +0000 |
| parents | 1238da4a7112 |
| children |
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.TH "SDL_JoystickGetBall" "3" "Tue 11 Sep 2001, 23:00" "SDL" "SDL API Reference" .SH "NAME" SDL_JoystickGetBall \- Get relative trackball motion .SH "SYNOPSIS" .PP \fB#include "SDL\&.h" .sp \fBint \fBSDL_JoystickGetBall\fP\fR(\fBSDL_Joystick *joystick, int ball, int *dx, int *dy\fR); .SH "DESCRIPTION" .PP Get the \fBball\fR axis change\&. .PP Trackballs can only return relative motion since the last call to \fBSDL_JoystickGetBall\fP, these motion deltas a placed into \fBdx\fR and \fBdy\fR\&. .SH "RETURN VALUE" .PP Returns \fB0\fR on success or \fB-1\fR on failure .SH "EXAMPLES" .PP .PP .nf \f(CWint delta_x, delta_y; SDL_Joystick *joy; \&. \&. \&. SDL_JoystickUpdate(); if(SDL_JoystickGetBall(joy, 0, &delta_x, &delta_y)==-1) printf("TrackBall Read Error! "); printf("Trackball Delta- X:%d, Y:%d ", delta_x, delta_y);\fR .fi .PP .SH "SEE ALSO" .PP \fI\fBSDL_JoystickNumBalls\fP\fR .\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:00